ran to the woods and rivulet which from one head of the Warwick, and continue almost without break to connect with the works at Wynn's Mill. This stream just mentioned, whatever be its name (the tern "Warwick," according to some, applying only to the tidal channel from the James River up as high as Lee's Mill), was inundated by a number of dams from near where its head is crossed by the epaulements mentioned down to Lee's Mill.

Below Lee's Mill the Warwick follows a tortuous course salt marshes of 200 yards or 300 yards in width, from which the land rises up boldly to a height of 30 or 40 feet.

The first group of works is at Wynn's Mill, where there is a dam and bridge. The next is to guard another dam between Wynn's and Lee's Mills. (This is the point attacked by General Smith on the 16th ultimo, and where Lieutenant Merril was wounded. The object of the attack was merely to prevent the further construction of works and feel the strength of the position.) A work of what extent is not now known, was at the sharp angle of the stream just above Lee's Mill, and a formidable group of works was at Lee's Mill, where there was also a dam and bridge. From Lee's Mill a Line of works extends across Mulberry Island, or is supposed to do so. At Southall's Landing is another formidable group of works, and from here, too, they extend apparently across to the James River. These groups of field works were connected by rifle trenches or parapets for nearly the whole distance. They are far more extensive than may be supposed from the mention of them I make, and every kind of obstruction which the country afford, such as abatis, marsh, inundation,&c., was skillfully used. The line is certainly one of the most extensive known to modern times.

The country on both side of the Warwick, from near Yorktown down, is a dense forest, with few clearings. It was swampy, and the roads impassable during the heavy rains we have constantly had, except where our own labors had chartered them.

If we could have broken the enemy's line across the isthmus we could have invested Yorktown, and it must, with its garrison, have soon fallen into our hands. It was not deemed practicable, considering the strength of that line and the difficulty of handling our forces (owing to the impracticable character of the country), to do so.

If we could take Yorktown or drive the enemy out of that place the enemy's line was no longer tenable. This we could do by siege operations. It was deemed too hazardous to attempt the reduction of the place by assault.

The plan of the approaches and their defenses, as determined upon and finally executed, is exhibited on the accompanying map. It was, in words, to open the first parallel as near as possible to the works of the enemy, and under its protection to establish almost simultaneously batteries along the whole front, extending from York River on the right to the Warwick on the left, a chord of about 1 mile in length. The principal approaches were directed against the east and of the main work, which was most heavily armed, and bore both on the water and land, and lay between Wormley's Creek and York River. There, also, were placed the most of the batteries designed to act against the land front, to enfilade the water batteries and to act upon Gloucester.

I designed at the earliest moment to open simultaneously with several batteries,and as soon as the enemy's guns which swept the neck of land between Wormley's Creek and the Warwick were crippled and their fire kept down, to push the trenches as far forward as necessary and to assault Yorktown, and the adjacent works.

The approaches to the batteries, the necessary bridges, and the roads to the depots had been vigorously pushed to completion by the troops under Generals Heintzelman and Sumner, and were available for infantry, and in some instances for artillery, on the 17th of April, when the batteries and their connections were commenced and labor upon them kept up night and day until finished. Some of the batteries on easy ground and concealed from the view of the enemy were early completed and armed and held ready for any emergency, but not permitted to open, as the return fire of the enemy would interfere too much with the labor on other and more important works. The completion of

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